The present invention relates to an apparatus and a method of controlling beverage dispensing machines, in particular of controlling automatic beverage dispensing machines for home or office use, or to be installed in food-service sites or in so called HoReCa (Hotel-Restaurant-Cafe) sites.
For the purposes of the present invention, the word “beverage” means the product resulting from several preparation methods such as, for instance, brewing, solubilisation of instant edible powders, freezing, chilling or heating drinking water, etc.
Available dispensing machines provide several types of beverages such as, for instance, coffee, tea, cappuccino, juices, chocolate, water, drinks, which are automatically prepared with no need for the user to intervene in the preparation process.
Usually preparation of a beverage is carried out by the dispensing machine according to preset sequences. Each preparation sequence requires the machine to perform one or more tasks such as, grinding a measured amount of coffee beans, brewing the coffee for a preset time lapse, mixing the liquid coffee with milk, etc. Each task is carried out by one or more machine units, for instance a boiler, a grinder, a mixer, a feeder, etc.
Recently, beverage dispensing machines have been provided with apparatuses for controlling their operation. Control apparatuses check several operating parameters of the related machine and eventually intervene to modify operation of one or more units to compensate undesired alterations in the beverage preparation process. For instance this allows for preserving the quality of the dispensed beverage despite of undesired changes of the machine operating parameters (i.e. the brewing parameters), or switching the machine into a “sold-out” condition when a certain ingredient is no more available.
Some beverage dispensing machines are equipped with micro-processors capable of executing multiple checks and controls over the machine units.
European patent application n. EP 04031014.6, in the name of Rhea Vendors S.p.A., discloses a method for controlling coffee dispensing machines through monitoring of real-time data concerning brewing parameters, comparing said real-time data to a set of historic data and/or threshold parameters and altering at least one of said relevant brewing parameters, when required to bring said real time parameters in line with said recorded parameters.
Dispensing machines are known provided with simple on-off switches which do control the presence of an ingredient in the related container, but this information is used to simply block dispensing of the beverage prepared with such ingredient, i.e. to set the machine in the “sold-out” condition.
For instance EP 0010448, in the name of “VGL IND LTD”, relates to an apparatus for indicating the availability of ingredients to be dispensed. The apparatus is provided with a light source and a sensor which together define a light path across the neck portion of a suitable ingredient container. When the ingredient level falls below the light path the incident light impinging the sensor is increased, thereby providing an indication that the ingredients are “sold out”. An alternative optical apparatus is disclosed in the Japanese patent application n. JP2004354143, in the name of “Fuji Seiki KK”.
Other known apparatuses provide recognition of an ingredient sold-out condition on the basis of the statistical evaluation of the ingredient consumption. For instance the average throughputs per ingredient type are taken into account, thereby deducting a correspondent theoretical amount at each dispensing cycle (reverse counting feature) and blocking the access to that particular dispensing cycle if the ingredient is estimated run out. These apparatuses do not tolerate changes in the ingredient throughputs from the estimated average values without occurring in mistakes when evaluating the sold-out condition for the ingredient. Another drawback of such apparatuses is that they require to re-set the “reverse counting” at each machine filling, usually by intervening on a suitable controller means, and also require to fully fill the container with the ingredient or, alternatively, to manually input the exact level of the container (or of each container) into a controller unit. These procedures are rather complex, potentially inaccurate and time consuming.
A problem common to known beverage dispensing machines relates to the proper dosing of the ingredient.
Dispensing machines are usually provided with an endless feeding screw for drawing a powder ingredient from the relevant container and supply it to another unit of the machine, for processing and beverage preparation. Such screw is located at the bottom of the container and is operated for a preset time, corresponding to a preset number of turns and, therefore, to a preset amount of powder. It is recognized that the ingredient dose supplied by the feeding screw depends on the pressure exerted by the mass of the ingredient on the portion of ingredient located at the inlet of the feeding screw. In fact when the container is almost empty, the pressure exerted on the ingredient at the inlet of the feeding screw is minimum, and a lesser amount of ingredient enters the screw. Therefore, the ingredient dose supplied by the feeding screw is less than the dose fed when operating with full container, this causing undesired changes in the operating parameters and in the characteristics of the dispensed beverage. The same or similar drawback has been found in “R&G” (roast and ground) coffee dispensing machines and in machines wherein coffee beans or ice-cubes are processed.
Still another problem of known beverage dispensing machines relates to clogging of the feeding screw by ingredient aggregates. In certain circumstances, such as at high humidity levels or when using hygroscopic ingredients, the same ingredients tend to aggregate and form lumps or bridges in the container. Aggregates interfere with normal free-flowing movement of the ingredient toward and within the feeding screw or other, equivalent drawing means. When such a situation occurs, attendance by an operator is required to disaggregate the lumps and restore the proper operation of the machine.